Traditional techniques for bonding powder metallurgy compacts, for example Metal Injection Molded (MIM) components, usually require applying a bonding catalyst to one or both of the mating surfaces of the components in a precise and controlled manner, followed by sinter bonding of the components. The efficacy of traditional sinter bonding is highly dependent on surface fit and usually requires a complicated sintering cycle. As a result, high volume production is usually cost prohibitive and difficult to achieve. Further, although a bond produced via sinter bonding may be sufficiently strong, it is difficult, if not impossible, to achieve a hermetic seal between joined components.
More recently, other bonding techniques have included bonding in the green- or brown-state using a polymer laminate disposed between the components to facilitate bonding. The “green-state” refers to the state of a component when removed from the molding machine. The “brown-state” refers to the state of the component after about 5% to about 85% of the binder is removed by a debinding process (e.g., immersing the component in a solvent bath or thermally treating the component). Forming the polymer layer between two green- or brown-state bodies complicates the manufacturing process and can plague high-volume production.
Further, orthopedic implants, for example prosthetic knee implants and hip cups, typically incorporate a porous metal layer to promote bone growth therethrough for enhancing attachment of the implant to adjacent bone tissue. Conventional manufacturing processes for such devices include casting or forging a portion of the implant and separately forming a porous layer on the portion, e.g., by plasma spraying of metal powder or sintering metal beads. Such traditional processes generally are expensive and time consuming.